The Crescent Nebula is an emission nebula in the constellation Cygnus and is about 4.700 light-years away.

The star, WR136, began its dying process a few hundred thousand years ago:
It first swelled up to a red supergiant and began to blow off its outer hydrogen layers – and it’s still expanding with about 80 km/s!!
As the star is heavy enough it’s begun to fuse helium in the core heating up the outer layers to 70.000 degrees (hotter than almost all other stars) which completely blows away the outer hydrogen layers.

The exposed core is now radiating charged particles at the rate of 1.700 km/s which has caught up and is colliding with the outer hydrogen layers creating the a shell of ionised hydrogen gas which is what we see as the Crescent Nebula.
The rest of WR136 is expected to end its life in a Supernova explosion in a few hundred thousand years from now.

The photograph consists of 102 sub-images taken over 3 nights (originally many more sub-images were taken but was rejected for various reasons).
The subs were taken with a ZWO ASI294MC Pro cooled camera on a guided SkyWatcher EQ6R Pro mount and a Newtonian SkyWatcher Explorer 650/130 reflector.

The imaging sessions were controlled by N.I.N.A. and the pre- and post processing was done in PixInsight.

It’s my second image session of the Crescent Nebula (the first was 2 years ago and can be seen here: Crescent Nebula 2020) and I’m happy to see the difference to the better! 🙂